The following prior art documents relate to the background to this invention:                1. Patent WO2009013533: MIM capacitor structure and methods of manufacturing the same.        2. U.S. Pat. No. 4,878,151: Anti-parallel capacitor.        3. U.S. Pat. No. 4,918,454: Compensated capacitors for switched capacitor input of an analog-to-digital converter.        4. U.S. Pat. No. 6,404,376: Capacitor array having reduced voltage coefficient induced non-linearities.        5. US Patent No. 2007200162: Reducing dielectric constant for MIM capacitor        6. US Patent No. 2004209423: Methods for reducing capacitor dielectric absorption and voltage coefficient.        
Various capacitors have been used in the fabrication of mixed analog and digital circuits. However, prior art integrated circuit capacitors have not been satisfactory in terms of VCC and the precision of capacitive charge distribution in a circuit.
In the past, there are several methods to reduce and/or eliminate the non-linearity of the voltage coefficient for a capacitor. In U.S. Pat. No. 4,878,151, issued on 31 Oct. 1989, an “anti-parallel” capacitor 100 has two capacitors connected which may achieve a constant voltage coefficient, if the polarity of one capacitor is connected to the reverse polarity of the other capacitor. Micheal J. Gallichio et al. states that the “anti-parallel” capacitor 100 is configured to cancel out the linear variation in the capacitance of each capacitor due to the reverse polarity of the two capacitors. The attached FIG. 1 shows a schematic diagram of the “anti-parallel” capacitor 100 of U.S. Pat. No. 4,878,151. Both capacitors 28 and 30 have a value of, say, X/2 and result in a total capacitance value of X.
Furthermore, U.S. Pat. No. 4,918,454, issued on 17 Apr. 1990, reveals that two capacitors 28 and 30, can be connected in parallel to form a capacitor array which has a lower voltage coefficient of capacitance.
However, the capacitance variation for real components is not only a linear voltage dependence. A cross-coupled parallel capacitor pair will eliminate a linear variation but will do nothing to diminish a non-linear change. These non-linear variations (eg curvature) in the capacitance versus voltage will not be removed by simply using an anti-parallel connection.